The role of conflict in the formation and maintenance of variant sex chromosome systems in mammals.

The XX/XY sex chromosome system is deeply conserved in therian mammals, as is the role of Sry in testis determination, giving the impression of stasis relative to other taxa. However, the long tradition of cytogenetic studies in mammals documents sex chromosome karyotypes that break this norm in myriad ways, ranging from fusions between sex chromosomes and autosomes to Y chromosome loss. Evolutionary conflict, in the form of sexual antagonism or meiotic drive, is the primary predicted driver of sex chromosome transformation and turnover.

The Modification of Offspring Stress-Related Behavior and the Expression of , and by a Western-Pattern Diet in .

The impact of early developmental experience on neurobiological pathways that may contribute to the association between diet and behavior have not yet been elucidated. The focus of the current study was to determine whether the impact of prenatal stress (PS) could be mitigated by a diet that stimulates the same neuroendocrine systems influenced by early stress, using a mouse model. Behavioral and genetic approaches were used to assess how a Western-pattern diet (WPD) interacts with PS and sex to impact the expression of anxiety-like behavior in an open-field arena, as well as the expression of the glucocorticoid receptor in the hippocampus, D1 dopamine receptors in the nucleus accumbens, and D2 dopamine receptors in the ventral tegmental area.

Sex chromosome transformation and the origin of a male-specific X chromosome in the creeping vole.

The mammalian sex chromosome system (XX female/XY male) is ancient and highly conserved. The sex chromosome karyotype of the creeping vole () represents a long-standing anomaly, with an X chromosome that is unpaired in females (X0) and exclusively maternally transmitted. We produced a highly contiguous male genome assembly, together with short-read genomes and transcriptomes for both sexes.

Haldane's rule in the placenta: Sex-biased misregulation of the Kcnq1 imprinting cluster in hybrid mice.

Hybrid phenotypes that contribute to postzygotic reproductive isolation often exhibit pronounced asymmetry, both between reciprocal crosses and between the sexes in accordance with Haldane's rule. Inviability in mammalian hybrids is associated with parent-of-origin placental growth abnormalities for which misregulation of imprinted gene (IGs) is the leading candidate mechanism. However, direct evidence for the involvement of IGs in hybrid growth dysplasia is limited.

Distinct evolutionary trajectories of V1R clades across mouse species.

Background: Many animals rely heavily on olfaction to navigate their environment. Among rodents, olfaction is crucial for a wide range of social behaviors. The vomeronasal olfactory system in particular plays an important role in mediating social communication, including the detection of pheromones and recognition signals.

Intergenerational effects of paternal predator cue exposure on behavior, stress reactivity, and neural gene expression.

Predation threat impacts prey behavior, physiology, and fitness. Stress-mediated alterations to the paternal epigenome can be transmitted to offspring via the germline, conferring a potential advantage to offspring in predator-rich environments. While intergenerational epigenetic transmission of paternal experience has been demonstrated in mammals, how paternal predator exposure might alter offspring phenotypes across development is unstudied.

Placental effects on the maternal brain revealed by disrupted placental gene expression in mouse hybrids.

The mammalian placenta is both the physical interface between mother and fetus, and the source of endocrine signals that target the maternal hypothalamus, priming females for parturition, lactation and motherhood. Despite the importance of this connection, the effects of altered placental signalling on the maternal brain are insufficiently studied. Here, we show that placental dysfunction alters gene expression in the maternal brain, with the potential to affect maternal behaviour.

Vocal divergence is concordant with genomic evidence for strong reproductive isolation in grasshopper mice ().

Behavioral barriers to gene flow often evolve faster than intrinsic incompatibilities and can eliminate the opportunity for hybridization between interfertile species. While acoustic signal divergence is a common driver of premating isolation in birds and insects, its contribution to speciation in mammals is less studied. Here we characterize the incidence of, and potential barriers to, hybridization among three closely related species of grasshopper mice (genus ).

Placental genotype affects early postpartum maternal behaviour.

The mammalian placenta is a source of endocrine signals that prime the onset of maternal care at parturition. While consequences of placental dysfunction for offspring growth are well defined, how altered placental signalling might affect maternal behaviour is unstudied in a natural system. In the cross between sympatric mouse species, and , hybrid placentas are undersized and show misexpression of genes critical to placental endocrine function.

Evolutionary patterns of major urinary protein scent signals in house mice and relatives.

Scent marks are important mediators of territorial behaviour and sexual selection, especially among mammals. The evolution of compounds used in scent marks has the potential to inform our understanding of signal evolution in relation to social and sexual selection. A major challenge in studies of chemical communication is that the link between semiochemical compounds and genetic changes is often unclear.

SNP variable selection by generalized graph domination.

Background: High-throughput sequencing technology has revolutionized both medical and biological research by generating exceedingly large numbers of genetic variants. The resulting datasets share a number of common characteristics that might lead to poor generalization capacity. Concerns include noise accumulated due to the large number of predictors, sparse information regarding the p≫n problem, and overfitting and model mis-identification resulting from spurious collinearity.

A High Quality Genome for , a Close Relative of House Mice with Unique Social and Ecological Adaptations.

Genomic data for the closest relatives of house mice ( species complex) are surprisingly limited. Here, we present the first complete genome for a behaviorally and ecologically unique member of the sister clade to house mice, the mound-building mouse, Using read cloud sequencing and assembly we produced a 2.50 Gbp genome with a scaffold N50 of 2.

Interspecies Variation in the Susceptibility of a Wild-Derived Colony of Mice to Pinworms ().

Pinworms are common parasites in wild and laboratory rodents. Despite their relative nonpathogenicity in immunocompetent models, pinworm infections add an unwanted variable and may confound some types of research. For this reason, health monitoring programs and biosecurity measures aim to minimize the spread of pinworm infections into colonies free from the organisms.

Asymmetric energetic costs in reciprocal-cross hybrids between carnivorous mice (Onychomys).

Aerobic respiration is a fundamental physiological trait dependent on coordinated interactions between gene products of the mitochondrial and nuclear genomes. Mitonuclear mismatch in interspecific hybrids may contribute to reproductive isolation by inducing reduced viability (or even complete inviability) due to increased metabolic costs. However, few studies have tested for effects of mitonuclear mismatch on respiration at the whole-organism level.

Gene regulation and speciation in house mice.

One approach to understanding the process of speciation is to characterize the genetic architecture of post-zygotic isolation. As gene regulation requires interactions between loci, negative epistatic interactions between divergent regulatory elements might underlie hybrid incompatibilities and contribute to reproductive isolation. Here, we take advantage of a cross between house mouse subspecies, where hybrid dysfunction is largely unidirectional, to test several key predictions about regulatory divergence and reproductive isolation.

Vocal ontogeny in neotropical singing mice (Scotinomys).

Isolation calls produced by dependent young are a fundamental form of communication. For species in which vocal signals remain important to adult communication, the function and social context of vocal behavior changes dramatically with the onset of sexual maturity. The ontogenetic relationship between these distinct forms of acoustic communication is surprisingly under-studied.

Sexual selection on protamine and transition nuclear protein expression in mouse species.

Post-copulatory sexual selection in the form of sperm competition is known to influence the evolution of male reproductive proteins in mammals. The relationship between sperm competition and regulatory evolution, however, remains to be explored. Protamines and transition nuclear proteins are involved in the condensation of sperm chromatin and are expected to affect the shape of the sperm head.

X-y interactions underlie sperm head abnormality in hybrid male house mice.

The genetic basis of hybrid male sterility in house mice is complex, highly polygenic, and strongly X linked. Previous work suggested that there might be interactions between the Mus musculus musculus X and the M. m.

Meiotic sex chromosome inactivation is disrupted in sterile hybrid male house mice.

In male mammals, the X and Y chromosomes are transcriptionally silenced in primary spermatocytes by meiotic sex chromosome inactivation (MSCI) and remain repressed for the duration of spermatogenesis. Here, we test the longstanding hypothesis that disrupted MSCI might contribute to the preferential sterility of heterogametic hybrid males. We studied a cross between wild-derived inbred strains of Mus musculus musculus and M.

The contribution of the Y chromosome to hybrid male sterility in house mice.

Hybrid sterility in the heterogametic sex is a common feature of speciation in animals. In house mice, the contribution of the Mus musculus musculus X chromosome to hybrid male sterility is large. It is not known, however, whether F1 male sterility is caused by X-Y or X-autosome incompatibilities or a combination of both.

Molecular phylogeny of hipposiderid bats from Southeast Asia and evidence of cryptic diversity.

Old World leaf-nosed bats (Hipposideridae) are among the most widespread and ecologically diverse groups of insectivorous bats in the Old World tropics. However, phylogenetic relationships in Hipposideridae are poorly resolved at both the generic and species levels, and deep genetic divergence within several Southeast Asian species suggests that current taxonomy underestimates hipposiderid diversity in this region. We used mitochondrial and nuclear sequence data to conduct the first extensive molecular phylogenetic analysis of Southeast Asian hipposiderid bats.

Geographic variation in the songs of neotropical singing mice: testing the relative importance of drift and local adaptation.

Patterns of geographic variation in communication systems can provide insight into the processes that drive phenotypic evolution. Although work in birds, anurans, and insects demonstrates that acoustic signals are sensitive to diverse selective and stochastic forces, processes that shape variation in mammalian vocalizations are poorly understood. We quantified geographic variation in the advertisement songs of sister species of singing mice, montane rodents with a unique mode of vocal communication.

Central vasopressin and oxytocin receptor distributions in two species of singing mice.

The neuropeptides arginine vasopressin (AVP) and oxytocin (OT) are key modulators of vertebrate sociality. Although some general behavioral functions of AVP and OT are broadly conserved, the detailed consequences of peptide release seem to be regulated by species-specific patterns of receptor distribution. We used autoradiography to characterize central vasopressin 1a receptor (V1aR) and OT receptor (OTR) distributions in two species of singing mice, ecologically specialized Central American rodents with a highly developed form of vocal communication.

Beating the boojum: comparative approaches to the neurobiology of social behavior.

Neuropeptides coordinate complex social behaviors important to both basic and applied science. Understanding such phenomena requires supplementing the powerful tools of behavioral neuroscience with less conventional model species and more rigorous evolutionary analyses. We review studies that use comparative methods to examine the roles of vasopressin and oxytocin in mammalian social behavior.

Conservation and diversity of Foxp2 expression in muroid rodents: functional implications.

FOXP2, the first gene causally linked to a human language disorder, is implicated in song acquisition, production, and perception in oscine songbirds, the evolution of speech and language in hominids, and the evolution of echolocation in bats. Despite the evident relevance of Foxp2 to vertebrate acoustic communication, a comprehensive description of neural expression patterns is currently lacking in mammals. Here we use immunocytochemistry to systematically describe the neural distribution of Foxp2 protein in four species of muroid rodents: Scotinomys teguina and S.